Muffler



United States Patent MUFFLER Lloyd E. Muller, Flint, Micln, assigner to General Motors Corporation, Detroit, Micln, a corporation of Delaware Application September 19, 1955, Serial No. 534,919 1 Claim. (Cl. 181 -54) This invention relates to mufilers for engines and has particular relation to mufflers applicable for use with high speed, high powered, internal combustion engines for automotive and other uses.

It is proposed to rigidly and economically construct a light weight, large capacity muiher that can be located in the limited space available beneath the floor in automotive vehicles as now constructed.

In the drawing:

Fig. 1 is a longitudinal sectional view of a mufiler embracing the principles of the invention;

Fig. 2 is a cross sectional view of the muffler disclosed by Fig. 1 and taken substantially in the plane of line 2--2 of Fig. 1;

Fig. 3 and 4 are fragmentary views of louvres employed in the acoustical coupling means with which the mufiler disclosed by the preceding figures is provided; Fig. 4 is taken substantially in the plane of line 4-4 on Fig. 3.

The mufller embracing the invention comprises an elongated, preferably oval, casing 11 which may be constructed in any suitable manner. In the present instance, the casing comprises outer and inner tubular walls 12 and 13, respectively, and between which insulating and sound deadening material 14 is employed. The casing has end walls 16 and 17 beaded or otherwise secured to the ends of the tubular walls.12 and 13. The interior of the casing 11 is divided by spaced and transversely disposed partitions 18, 19, 21 and 22 to provide resonating chambers 23, 24 and 26 and expansion chambers 27 and 28.- A transverse partition 29 also extends across the casing 11 between the partition 22 and the end wall 17 to provide an additional resonating chamber 31 at one end of the casing 11. An inlet conduit 32 extends within the casing 11,,through the end wall 16, the spaced partitions 18 and 19, and terminates in an opening in the partition 21 in such a way as to communicate with the expansion chamber 28. An outlet conduit 33 communicating at the inlet end thereof with the expansion chamber 27 also extends from the casing 11 through the partition 19, the spaced partitions 21 and 22, th'e partition 29 and the end wall 17. An intermediate conduit 34 connects the expansion chambers 27 and 28 through partitions 19 and 21. The intermediate conduit 34 may be located in any desirable manner within the casing 11, although in thepresent instance the conduit 34 is located at one side of the casing 11 and at one side of the inlet and outlet conduits 32 and 33.

An acoustical coupling tube 36 opens into theresonating chamber 26 from the expansion chamber 23 and in alignment with the inlet conduit 32. An acoustical coupling tube 37 opens into the resonating chamber 23 from the expansion chamber 27 and in alignment with the outlet conduit 33. The resonating chamber 24 is connected to the inlet conduit 32 through an elongated concentric tube 38 disposed about the inlet conduit 32 and extending through the partitions 18 and 19 from a region adjacent the end wall 16. The tube 38 is spaced from the conduit 32 to provide an annular coupling passage 39, the inner end of which isclosed by a flanged connecting ring 41 extending-between the inner end of the tube 38 and the adjacent part of the conduit 32. The inner end of the coupling passage 39 is connected to the interior of the conduit 32 by louvred opening means 42 formed in the conduit 32. The opening means 42 may be formed by groups of louvres such as that indicated at in Figures 3 and 4. An inner casing 43 is also disposed in the resonating chamber 26 and extends between the partitions 22 and 29 in spaced relation to the outlet conduit 33 to provide small resonating chambers 44 and 46. The chambers 44 and 46 are separated from one another by a flanged ring indicated at 47. The small resonating chambers 44- and d6 are connected to the outlet conduit 33 by louvred openings indicated generally 42. The resonating chamber 31 is connected to the outlet conduit 33 by louvred opening means 48 formed in the conduit 33 within the chamber 31.

The resonating chambers 23, 24, 26, 31, 44 and 46 are tuned to sounds of different frequencies emanating from the engine with which the muffler 10 is employed and traversing the muflier through the exhaust passage provided by the inlet conduit 32, the expansion chamber 28, the intermediate conduit 34, the expansion chamber 27 and the outlet conduit 33.

I claim:

A. mufiler for engines comprising an elongated casing having a plurality of spaced resonating chambers formed therein, said resonating chambers being formed by transverse partitions extending across said casing and being spaced by pairs of said partitions spaced from one another to provide expansion chambers in said casing between said resonating chambers, an inlet conduit extending within said casing and across one of said resonating chambers and one of said expansion chambers and another of said resonating chambers and communicating with another of said expansion chambers at the outlet end thereof, an outlet conduit extending with-in said casing and across a pair of resonating chambers and said another of said expansion chambers and said another of said resonating chambers and communicating With said one of said expansion chambers, the sections of said inlet and outlet conduits extending across said expansion chambers being closed against communication with said expansion chambers, an imperforate intermediate conduit connecting said one and said another of said expansion chambers, and acoustical coupling means connecting said resonating chambers to the exhaust gas circulating passage provided by the continuous series connection of said inlet conduit and said another of said expansion chambers and said intermediate conduit and said one of said expansion chambers and said outlet conduit, said circulating passage circulating all of said exhaust gas successively through said inlet conduit and said another of said expansion chambers and said intermediate conduit and said one of said expansion chambers and said outlet conduit, said acoustical coupling means connecting said inlet conduit to said another of said resonating chambers through perforations in said inlet conduit and the annular space between said inlet conduit and a tube surrounding said inlet conduit and extending through and supported in openings in one of said pairs of partitions forming said one of said expansion chambers, said acoustical coupling means also connecting said expansion chambers to said one of said resonating chambers and to one of said pair of resonating chambers and being aligned with said inlet conduit and said outlet conduit, said acoustical coupling means also connecting said outlet conduits to the other of said pair of resonating chambers.

References Cited in the file of this patent UNITED STATES PATENTS Deremer Dec. 1, 1953 

